The present invention relates to an electric wire holding case which prevents oil from leaking through an electric wire extending into the oil cover of a transmission case or the like.
FIG. 4 is a longitudinally sectional view of a conventional electric wire holding case B which prevents oil from leaking through electric wires 51a and 51b extending into the oil cover 41 of a transmission case and was disclosed in the Japan Patent Examined Publication No. Hei. 1-59467. The case B has a cylindrical body 40, and a rubber plug 52. The body 40 is made of a synthetic resin and secured in the hole 45 of the oil cover 41 at an engagement claw 43 and a flange 44 which are provided on the peripheral portion of the body. A reference numeral 42 in FIG. 4 shows the interior of the transmission case. An O-ring 46 is fitted in the peripheral portion of the case body 40 to seal the portion to prevent the oil from leaking through between the portion and the oil cover 41. The conductors 49a and 49b of the electric wires 51a and 51b are exposed by peeling the insulators 48a and 48b thereof at one end of each of the wires, and then connected to each other by a terminal 50. The electric wires 51a and 51b are laid inside the inner portion 47 of the case body 40. The rubber plug 52 is fitted in the inner portion 47 at one end thereof. The insulator-unpeeled portion of the wire 51a is laid through the rubber plug 52 so that the wire is sealed on the insulator 48a thereof by the plug. A synthetic resin 52, which is such as an epoxy resin and hardens when being set, is filled and solidified inside the inner portion 47 at the other end thereof so that the exposed conductors 49a and 49b of the electric wires 51a and 51b are embedded in the resin. The conductors 49a and 49b are exposed for one purpose of connecting them to each other, and another purpose of causing the resin 52 to stop the oil coming through between the insulator 48a and conductor 49a of the electric wire 51a due to capillary attraction. A waterproof cover 55 of rubber is fitted on the body 40 of the holding case B around the electric wire 51b. Since the resin 52 is solidified to firmly adhere to the inner surface 53 of the case body 40, the joint 54 of the conductors 49a and 49b is firmly held to prevent the electric wires 51a and 51b from going out of the holding case B. However, since the resin 52 is solidified to harden, it does not follow the conductors 49a and 49b in the thermal expansion and contraction thereof well enough and is likely to undergo a crack to let the oil leak. This is a problem. Besides, it is difficult to position the joint 54 of the conductors 49a and 49b in the body 40 of the holding case B in embedding the joint therein. This is also a problem.